The present study aims to study the effect of low viscous biofuel, namely pine oil (PO) and orange oil (O) blending with Jatropha methyl ester (JOME) along with exhaust gas recirculation (EGR) on NO-smoke tradeoff in a single-compression ignition (CI) engine. Two blends of pine oil and orange oil (30% by volume) with JOME were prepared and tested at 10%, 15%, and 20% EGR rates for various load conditions and compared with base fuels. JOME operation increased NO emission by 4% and reduced smoke opacity by 10% in comparison to diesel at maximum load condition. Poor physical properties of JOME, namely high viscosity and inferior volatility leads to reduced brake thermal efficiency with higher HC and CO emissions. Blends of JOME with low viscous biofuel reduces smoke emission with a further increase in NO emission in comparison to JOME as a result of combustion enhancement. Addition of EGR with JOME70 + PO30 and JOME70 + O30 aids in the reduction of NO emission with a slight increase in smoke opacity. Considering the NO-smoke tradeoff, JOME70 + O30 + EGR (10%) is optimum, NO emission is reduced by 14% and 11% in comparison to JOME and diesel and smoke opacity is reduced by 5% and 15% in comparison to JOME and diesel at maximum load, respectively.

Impregnating CuCl₂ on AC (activated coke) support to synthesize xCuCl₂/AC showed superior activity with higher 90% Hg⁰ removal efficiency at 80–140 °C, as well as a lower oxygen demand of 2% O₂ for Hg⁰ removal. The acceleration on Hg⁰ removal was observed for NO and SO₂. The BET, SEM, XRD, XPS, TPD, and FT-IR characterizations revealed that the larger surface area, sufficient active oxygen species and co-existence of Cu⁺ and Cu²⁺ may account for the efficient Hg⁰ removal. In addition, the low demand of gaseous O₂ was contributed to higher content of active oxygen and formed active Cl. After adsorbing on Cu sites, Cl sites, and surface functional groups, the Hg⁰₍ₐdₛ₎ removal on xCuCl₂/AC was proceeded through two ways. Part of Hg⁰₍ₐdₛ₎ was oxidized by active O and formed Hg⁰, and the other part of Hg⁰ combined with the active Cl, which was formed by the activation of lattice Cl with the aid of active O, and formed HgCl₂. Besides, the Hg²⁺ detected in outlet gas through mercury speciation conversion and desorption peak of HgCl₂ and Hg⁰ further proved it. As displayed in stability test and simulated industrial application test, CuCl₂/AC has a promising industrial application prospect.

Assessing the current farm-level efforts of climate change adaptation is essential to distinguish their usefulness and implying policy level advance measures for future. The present study investigated cotton farmers’ climate change adaptation and its impact on increasing cotton productivity and net cotton income in Punjab province of Pakistan. A pretested and well-structured questionnaire was used for data collection of 480 cotton farmers from three major cotton-producing divisions of cotton-wheat zone of Punjab, Pakistan. Logistic regression analysis approach was used in this study to find out the factors of adaptation and propensity score matching method employed to identify connecting adaptation impact on cotton productivity and cotton income. Empirical estimates of this study indicated as owing to some external and internal constraint farmers were limited focused on adaptation while conscious about adverse effects of climate change. Usage of required and recommended types of fertilizer, variation in planting dates, and changing varieties of crop were main adaptation strategies implemented by cotton farmers. Cotton farmers’ adaptation decision was significantly influenced by some major factors as weather forecasting, market information, easy access to agricultural extension services, farming experience, and education of cotton farmer. Farm-level increase in cotton productivity and net cotton crop income was direct while overall increases in national output and improving rural area farmer well-being were indirect and significant outcomes of implementing climate change adaptation of cotton farmers. Cotton farmers were using various combinations of adaptation strategies and achieving more benefits regarding their crop productivity and net returns. Findings of the study suggest need for larger investment in farm-level extension services, farmers’ schooling, and develop climate change institutional setup for enhancing farmers’ adaptation capability to increasing cotton productivity, improving well-being of farming community, and securing agriculture from future climatic uncertainties. Future policies must deal with farm-level limitations of advanced adaptation measures like making available information and sustaining sponsoring soil conservation practices, launching climate smart varieties and advanced adaptation measures based on various agro-ecological zones.

With the increase of carbon dioxide concentration in the atmosphere, the living environment of human beings is seriously affected. As a high carbon emission industry in China, thermal power enterprises are the key areas of carbon emission reduction in China. This paper first uses Super-SBM model to measure the performance of China’s 18 major thermal power enterprises in 2009–2018 from a static point of view. After considering the carbon emission constraints, it analyzes the degree of change in enterprise performance, and finds that the impact of carbon emission constraints on enterprise performance is not absolute. After that, with the help of Malmquist index model, this paper discusses the dynamic changes of thermal power enterprises’ performance under carbon emission constraint in recent 10 yrs. The results show that the overall performance of carbon emission constraint is in a weak regression stage and summarizes the disadvantages of different enterprises. On the basis of the research conclusion, this paper puts forward countermeasures and suggestions to further improve the performance of Chinese thermal power enterprises under the carbon emission constraints in the future, which is conducive to different enterprises to optimize their own disadvantages.

Groundwater is a primary source of living which also requires preservative measures for furture generations. Due to the lack of effective management technologies, the wastewater generated by rapid urbanization and industrialization is being disposed untreated, leading to groundwater contamination, caused by infiltration and accumulation. This problem has become more intense in major cities of India. The present work is based on determining the water quality using fuzzy index developed for the Perambalur district, Tamilnadu, India, from where 30 groundwater samples were collected from bore well as well as dug well sources. The research focusses mainly on chemical parameters like total hardness (T.H.), total dissolved solids (TDS.), potential hydrogen (pH), calcium (Ca²⁺), magnesium (Mg²⁺), potassium (K), sulphates (SO₄²⁻), total nitrates (NO₃ + NO₂), fluoride (F), bicarbonate (HCO₃), carbonate (CO₃²⁻) and chloride (Cl²⁻). These parameters were assessed for fuzzy water quality index (FWQI) model, and the index was designed concerning Mamdani fuzzy inference system. Five FIS models with different linguistic variables were developed based on triangular membership function with the implementation of 189 numbers of rules. Finally, fuzzy model was classified into five categories, such as excellent, good, poor, very poor and not-suitable. Based on the results obtained from this model, 6 samples were classified into excellent, 8 samples into good, 12 to poor, 3 to very poor and 1 to not-suitable. In connection with that, the results of proposed model were compared with the output obtained from the deterministic method.

Water treatment sludge (WTS) is abundantly produced in the world; the waste contributes to the environmental problems. Therefore, for WTS utilization, aluminum leaching was employed using hydrochloric acid in this study. Al leaching efficiency increased from 72% to 80% as hydrochloric acid concentration increased from 1 to 4 M. Decreasing the particle size and increasing the temperature increased Al leaching efficiency. The proposed kinetic model revealed that the rate-controlling step followed a series of two leaching mechanisms: initially controlled by product-layer diffusion and then by a chemically controlled reaction. For instance, at 70 °C, the initial stage is well fitted by product-layer diffusion (R² = 0.87) compared to R² = 0.60 for chemical reaction; while for the second stage, R² = 0.95 was observed via chemical reaction compared to R² = 0.74 for product-layer diffusion. The activation energies in these two stages were 9.58 kJ/mol and 10.73 kJ/mol, respectively. The proposed model was well validated by using data from literature and thus will be useful for other applications of leaching and extraction processes.

The aim of this study was the valorization of titanium flakes (waste) from titanium and titanium alloy ingot production factories and using in applications related to metals recovery as retention bed for some trace metals. The titanium flakes were anodized for surface nanostructuration with TiO₂ nanotubes and then annealed in order to increase the surface stability. The nanostructured titanium flakes were loaded and pressed in a retention column linked with inductively coupled plasma spectrometer (ICP-OES). This system allowed determination of trace elements such as beryllium, lanthanum, lutetium, and ytterbium from sample solutions. Beryllium recovery percentage was over 90%, while lanthanides have just a satisfactory recovery percentage (about 65% Yb and Lu and 50% La). The TiO₂ nanotube architecture was not affected during utilization being able to perform for a long time. A thermodynamic and kinetic study was done for beryllium due to its successful adsorption recovery percentage. The obtained results showed that the titanium waste is a promising material for rare earth and relatively rare earth elements retention and recovery. Graphical abstract Graphical abstract

Previous researches have confirmed that modified nanoscale carbon black (MCB) can decrease the bioavailability of heavy metals in soil and accumulation in plant tissues, resulting in the increase of biomass of plant. However, as a nanoparticle, the effects of MCB on plant cell morphology and microbial communities in Cd-contaminated soil are poorly understood. This study, through greenhouse experiments, investigated the effects of MCB as an amendment for 5 mg·kg⁻¹ Cd-contaminated soil on plant growth, plant cellular morphogenesis, and microbial communities. Two types of plants, metal-tolerant plant ryegrass (Lolium multiflorum), and hyperaccumulator plant chard (Beta vulgaris L. var. cicla) were selected. The results indicated that adding MCB to Cd-contaminated soil, the dry biomass of shoot ryegrass and chard increased by 1.07 and 1.05 times, respectively, comparing with control group (the treatment without MCB). Meanwhile, the physiological characteristics of plant root denoted that adding MCB reduced the damage caused by Cd to plants. The acid phosphatase activity of soils treated with MBC was higher and the dehydrogenase activity was lower than control group during whole 50 days of incubation, while the urease and catalase activity of soils treated with MBC were higher than control group after 25 days of incubation. When compared with the treatment without MCB, the abundances of nitrogen-functional bacteria (Rhodospirillum and Nitrospira) and phosphorus-functional bacteria (Bradyrhizobium and Flavobacterium) increased but that of nitrogen-functional bacteria, Nitrososphaera, declined. The presence of MCB resulted in increased microbial community abundance by reducing the bioavailability of heavy metals in soil, while increasing the abundance of plants by increasing the amount of available nitrogen in soil. The result of this study suggests that MCB could be applied to the in-situ immobilization of heavy metal in contaminated soils because of its beneficial effects on plants growth, root cellular morphogenesis, and microbial community.

Sustainable drainage systems (SuDS) have emerged as an effective and attractive approach for stormwater management, prevention of water pollution and flood control due to its sustainable, environmentally friendly and cost-effective approaches. One of the SuDS devices widely used to infiltrate, store and treat surface runoff which allows it to recharge groundwater is the pervious paving systems (PPS). Previous studies have demonstrated relatively high pollution removal efficiencies typically ranging from 98.7% for total hydrocarbons to 89% of COD. Although a small number of the studies have assessed the performance characteristics of the PPS system in long-established installations in terms of retention of pollutants, hydrological features, biodegradation of pollutants etc., none has assessed the risk of potential groundwater and soil pollution by pollutants such as metals retained in the PPS materials either as a disposed waste material (in the case of used geotextiles) or during re-use as secondary aggregates. Thus, this study evaluated potential risks associated with the decommissioning and beneficial use of wastes produced during the disassembly of a PPS. The authors believe that this was the first PPS to be addressed in this way. The method involved the determination of leachable concentrations of 14 metals in the PPS samples made up of extracts from the model profile which included the geotextile fibre (G), dust alone (D), aggregates and dust (AD), aggregates alone (AA) and pavement blocks (P) which were analysed and compared with two different groups of regulatory threshold limits. The results showed that the measured concentrations of all the metals were below the appropriate threshold values for irrigation purposes as specified by FAO and USEPA. Furthermore, results all indicated that the dismantled materials were all below EU LFD WAC limits for inert waste, indicating relative ease of disposal and suitability for use as recycled aggregate. This, admittedly limited data, indicates that recycling of aggregates from demolition wastes arising from end of life PPS would not be limited by the potential leaching of heavy metals, including re-use within another PPS. This would minimise dependence on virgin aggregates and hence reduce rate of exploitation of natural resources and improve sustainability score card of SuDS.

Bushehr, a port along the northern part of the Persian Gulf, has repeatedly encountered dust storms in recent years but there is not been a comprehensive study on the PM₂.₅ contents in this region. The present study reports the characteristics and health risks of atmospheric PM₂.₅-bound heavy metals (HMs) in Bushehr from December 2016 to September 2017. A total of 46 samples were analyzed, and a high volume air sampler equipped with quartz fiber filters was used for sampling. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was also used for HMs analyses. Risk assessment and hazard index (HI) of these metals were computed by using USEPA’s exposure parameters. The results showed that the average 24-h mass concentration of PM₂.₅ ranged from 22.09 to 292.45 μg/m³. The results also indicated that 95.65 and 82.61% of the samples were higher than WHO and EPA guidelines for 24-h PM₂.₅. Also there was no statistically significant relationship between wind direction and PM₂.₅.The average concentration levels of seven measured metals (Cd, Co, Cr, Fe, Ni, Pb, and V) in the PM₂.₅ samples were in the range of 6.03 ng/m³ to 1335.94 ng/m³, and the order of their concentration was Fe > Ni > Pb > Cr > Cd > V > Co. Principal component analysis (PCA) showed that PM₂.₅-bound heavy metals were categorized in three groups. The ecological risk level of calculated metals was very significant, and the major contribution of the ecological risk was related to Cd. The highest HQ in children and adults was related to Cr, and overall HI in children was higher than adults. Also the RI values of Cr in both groups of children and adults were indicated high risk of developing cancer in human.